The present invention relates to catheters and catheter components and, more particularly, to catheters and catheter components including guidewire lumens with sleeves.
Catheters used to treat, e.g., blocked arteries in coronary, peripheral, and neurovascular fields are typically guided to a treatment site by riding over a guidewire. Although the guidewire is sometimes coated with a friction-reducing material such as TEFLON, there is generally some friction when a plastic catheter is pushed over the wire.
In the past, in balloon catheters, polyethylene was used as the balloon material in the catheter. This allowed the use of low friction, High Density Polyethylene (HDPE) as the lumen for the guidewire. A low profile heat bond could be performed at the distal tip of the balloon and the guidewire lumen to allow for a smooth transition and a soft tip.
As more advanced and stronger materials have been developed for the balloon, such as Polyester (PET), Nylon, and Acrylon (Acrylonitrile), a need for an alternative to HDPE has arisen. HDPE as a single material cannot be heat bonded to materials such as Polyester, Nylon, and Acrylon. Some of the materials that can be bonded to Nylon balloons include Polyether Block Amide (PEBAX) and Nylon, however, these materials tend to have higher surface friction than HDPE. One solution has been to coextrude an inner layer of HDPE or TEFLON and an outer layer of some other material, such as PEBAX. This is more costly than an HDPE extrusion, and the coextrusion can result in delamination. Alternatively, an adhesive bond has been used. However, adhesive bonds tend to be undesirably stiff and have a relatively high profile.
Materials with low surface friction such as HDPE, and various fluoropolymers such as PolyTetraFluoroEthylene (PTFE) (also known as TEFLON as manufactured by DuPont), TetraFluorEthylene-Perfluorpropylene (FEP), and PerFluoroAlkoxy (PFA), cannot be heat bonded to many modern balloon materials and are difficult to process. Materials presently used as the guidewire lumen for Nylon balloons are commonly Polyether Block Amide (PEBAX), Nylon 11, Nylon 12, or blends of these materials. Materials used for PET and Acrylon balloons are Hytrel and PET/Polyurethane blends. Polyurethane balloons used for neuro applications also commonly use polyurethane or PEBAX inner wire lumens. All of these materials have high surface frictions at body temperature and have the potential to interfere with guidewire movement.
It is desirable to provide a material suitable for use in a catheter having a low surface friction and that is flexible and easy to process. It is particularly desirable to provide such a material for use in connection with a guidewire lumen.
In accordance with an aspect of the present invention, a guidewire lumen for a catheter comprises a tubular portion and a sleeve disposed over less than an entire length of the tubular portion, the tubular portion being formed of a first polymer and the sleeve being formed of a second polymer, the second polymer comprising one or more of a polyamide, a nylon, a polyether block amide, and polyurethane.
In accordance with another aspect of the present invention, a guidewire lumen for a catheter comprises a tubular portion formed of a first material and a sleeve formed of a second material disposed around part of the tubular portion, and a metallic marker band disposed around a portion of the tubular portion, the sleeve being disposed over the marker band and extending from proximate a distal end of the tubular portion to a point proximal of and proximate the marker band.
In accordance with another aspect of the present invention, a method of making a catheter comprises providing a sleeve over less than an entire length of a tubular portion of a guidewire lumen, the tubular portion being formed of a first material and the sleeve being formed of a second material, providing a marker band over the tubular portion and beneath the sleeve, and bonding the sleeve to a catheter component.
In accordance with another aspect of the present invention, a catheter comprises a guidewire lumen comprising a tubular portion and proximal and distal sleeves disposed over less than an entire length of the tubular portion, the tubular portion being formed of a first material and the sleeves being formed of a second material, and a metallic marker band disposed between the distal sleeve and the tubular portion, a balloon bonded to the distal sleeve, and a catheter shaft bonded to the proximal sleeve.